Circuit controller



-March 9, 1943.

CIRCUIT CONTROLLER Original Filed March so, 1932 2 Sheets-sheaf. 2

N. c. SCVHELITENGER A '2 ,313,291

- Patented Mar. 9, 1943 CIRCUIT CONTROLLER Newton 0. Schellenger,Chicago Telephone S El Paso, Tex, assignor to upply Company, Elkhart,

Ind, a corporation of Indiana Original application March 30, 1932,Serial No.

now Patent No.

2,198,277, dated April 23, 1940. Divided and this application March 22,1940, Serial No.

7 Claims.

This invention relates to circuit controllers or electric switches, andrefers particularly to a snap switch adapted to be combined with avolume control or other similar radio control instrumentality to formone compact unit.

This application is a division of the copending application of Newton 0.Schellenger, Serial No. 602,006, filed March 30, 1932, now Patent No.2,198,277.

One of the primary objects of this invention is to provide a snap switchof exceptionally compact construction and reliable in operation andwhich lends itself readily methods of manufacture.

In the interest of simplicity, it is a further object of this inventionto provide a switch wherein all moving parts are mounted directly in aninsulating casing or housing which eliminates the necessity for separateframe structures to carry the moving parts and in which the contactor isdirectly incorporated in the mechanical structure of the switch toeliminate the usual yoke and insulating mounting.

Another, object of this invention is to provide a switch structurewherein the actuating mechanism is insulated from the live parts so thatthe need for electrical clearances within the switch itself is avoidedand a more compact construction made possible.

Another object of this invention is to provide a switch or circuitcontroller wherein the movto low cost production able contactor is madeup of two portions of dissimilar metal, one of which provides thenecessary mechanical strength and rigidity, and the other of which isresilient to insure good contact upon switch closure.

Another object of this invention is to so arrange the composite elementsof the contactor that the resilient portion thereof constitutes the maincurrent carrying element, while the other provides an arcing tip toprotect the current carrying member from the destructive effects ofarcing during opening of the switch.

Another object of this invention is to provide an improved manner ofsupporting and carrying the toggle spring which acts to hold thecontactor in one position or the other.

Still another object of this invention is to provide a switch of thecharacter described having a simple kickoff embodied therein by whichthe contactor may be manually propelled in the event of its tendency tostick in either open or closed position.

A still further object -of this invention resides in the provision of anexceedingly simple manner of mounting the switch on a rheostat or othercontrol instrumentality to combine therewith in .the formation of acompact unitary structure and to enable switch actuation from theoperating member of the control instrumentality.

In this connection, it is another object of the present invention toprovide a switch so designed and constructed as to enable itscombination with a volume control or other control instrumentality insuch a manner that a short operating lever on the switch cooperates witha relatively long driving arm driven from the shaft of the controlinstrumentality so that a slight rotation of the control shaft issuflicient to operate the switch.

A still further object of this invention isto form the switch actuatingmember or operating ing lever and thus also preclude the possibility ofgrounding the switch parts through the rheostat.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed, and more particularly defined by the appended claims, itbeing understood that such changes in theprecise embodiment ofthehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate one complete example of thephysical embodiment of the invention, constructed in accordance with thebest mode so far devised for the practical application of the principlesthereof, and in which:

Figure 1 is an external switch embodying this invention;

- Figure 2 is a plan view of, the switch mounted on the metal cover of.a volume control which is broken away to show the internal structure ofthe switch, said view'showing the switch open;

Figure 3 is a view similar to Figure 2 but omitting the volume controlcover andillustratin the switch in a partially open position;

Figure 4 is a view similar to Figure 3 illustrating the switch closedand the manner in which the kickoff functions to force-its opening;

Figure 5 is a cross sectional view through the switch with the movableelements thereof on dead center;

Figure 6 is a fragmentary sectional view on the actuating member oroperat: f-

perspective view of a which would be used in production to plane of theline 6-6 of Figure 4 illustrating the manner in which the contactsengage Figure 7 is a view similar to Figure 6 illustrating the manner inwhich one element of the contactor provides an arcing tip, said viewbeing taken on the plane of the line 1-1 in Figure 3;

Figure 8 is a detail sectional view through the pitman assembly on aplane adjacent to the switch actuating lever or cam;

Figure 9 is a perspective view of the switch actuating lever or cam;

Figure 10 is a partial cross sectional view through a combined switchand volume control unit constructed in accordance with this invention; 1

Figure 11 diagrammatically illustrates the manner in which the switch isdriven from the volume control;

Figure 12 is a perspective exploded view show ing in detail the volumecontrol cover which serves as an electrostatic shield between the switchand the volume control and the insulating gaskets interposed between theswitch and the cover;

Figure 13 is a plan view of the, eccentric switch driving lever shown inFigure 10 illustrating the same in its condition before attachment tothe operating shaft; and

Figure 14 illustrates the lever of Figure 13 mounted on the shaft.

Referring now particularly to the accompanying drawings, in which likenumerals indicate like parts, the numeral 5 designates the body orhousing within which the switch mechanism is mounted. This 'body orhousing is made of insulating material and is preferably molded ofBakelite or other suitable material. Its general configuration is thatof a triangular shallow box having a bottom wall 6 and a side wall 1extending therefrom.

Lugs 8 project laterally from the side walls to provide for theattachment of the entire 'assembled switch structure to the back of avolume control or rheostat, as illustrated in Figure 10; To this end,the switch housing is secured to a circular cup-shaped metallic .cover 9by rivets,

screws, or other suitable means which enter the lugs 8.

Attention is directed to the fact that the top faces of the lugs lie asubstantial distance below the outer or top surface of the housing. As aconsequence, the heads or upset ends of the rivets secure the switchhousing to the metal cover, are protected from contact with liveterminals on the exterior of the housing or the leads attached thereto.

Attention is also directed to the fact that the edge of the side walllies in a single plane. This enables the switch housing to be mounted ona flat support with a tight fit between the support and the entire sidewall edge.

The metal cover 9 closes the open top of the switch housing except foran opening H through which a driving connection is established betweenthe volume control and the switch mechanism in a manner to behereinafter described.

The metallic cover plate 9 thus serves as an electrostatic shield orbarrier between the switch mechanism contained within the housing andthe variable resistance mechanism of the volume control to behereinafter described.

The switch mechanism comprises a stationary contact I2 and a cooperatingmovable contactor, indicated generally by the numeral l3. movablecontactor is pivoted on a stud l4 secured The in the apex of the switchhousing to swing with an arcuate motion flatwise across the bottom wall6 of the housing to and from engagement with the stationary contact l2.'

The stationary contact I! is secured in place on a shelf l5 formedwithin the switch housing by a rivet Or other securing means IS. Therivet l6 also passes-through a terminal l1 seated in a recess or pocketformed on the exterior of the bottom wall 6. The rivet thus electricallyconnects the stationary contact with the terminal l1.

The stationary contact has'two substantially right-angularly disposedarms, one of which projects beyond the edge of the shelf l5 to be spacedfrom the adjacent inner surface of the bottom wall and provide theportion with which the contactor engages. Rotation of the stationarycontact about its pivot is prevented by having its arms engage theadjacent side walls of the housing, as at l8.

The movable contactor [3 comprises two superimposed arms l9 and 20 heldassembled by tongues 2| extended from the sides of the arm is andengagedover the arm 20. The arm I9 is made of relatively stiff metal such ashard brass and provides the mechanical strength and rigidity for thecontactor. The arm 20, which is made of relatively more resilientmaterial such as phosphor bronze, provides the main current carryingportion of the contactor and the spring contact pressure to insure goodelectrical contact with the stationary contact.

Both contactor arms are apertured to engage the mounting stud l4, andboth are offset, as at 22, for a purpose to be hereinafterdescribed.

The lateral or side edges or both contactor arms which face thestationary contact are flared outwardly, as at 23 and 24, to facilitateengagement of the contactor with the stationary contact.

Upon enfagement of the contacts, the projecting portion of thestationary contact enters between the outer portions of the contactorarms, the arm 20 flexing to provide spring contact pressure. Theengagement between the stationary contact and the movable contactor isthus comparable to that of a knife switch.

As illustrated in Figures 6 and '7, the flared ends 23 and 24 of thecontactor arms l9 and 20, respectively, are so disposed that duringopening the flared end 23 leaves the stationary contact last and therebyserves as an arcing horn or tip. As a consequence, the contact engagingportion of the spring arm 20 is not subjected to the destructive arcingforces. This insures a good clean contact between the stationary contactand the contactor arm 20.

Provision is also made against the accumulation of corrosion on theflared edge 23 of the contactor arm l9 which, if permitted, wouldinterfere with its functioning as an arcing horn or tip and throw partof the arcing load onto the edge 24.

The protection against this possibility is specifically illustrated inFigure 7. 'It consists in having the contactor arm l9 normally depressedbelow the plane of the top surface of the stationary contact so that theflared end 23 rides up and down the edge of thestationary contact underspring tension as the switch closes and opens.

The contactor is electrically connected with a terminal 25 through thestud l4. The terminal 25, like the terminal I1, is received in a recessor pocket on the exterior of the bottom wall 6 where it is held by a nut26 or other suitable securing means by which the stud is held assembledwith the housing 5.

The limits of motion of the contactor are defined by inward projectionsor bosses 21 and 28 extending from the side walls of the housing. Motiontoward open position is defined by the engagement of the contactor withthe projection or boss 21; while motion toward switch closing positionis defined by the engagement of the contactor with the projection orboss 28. These inward projections or bosses also provide kickoffabutments which function in a manner to be hereinafter described toassure positive opening and closing motion of the contactor.

The contactor is yieldingly urged to either of it limits of motion by atoggle spring 29. This springis confined between an abutment 30 on Whenthe lever or cam engages the side wall portion ll. the directionoffspring thrust is such aslto yieldlngly hold the .contactor in itsopen position, as shown in Figure 2. When the lever or cam engages thestop portion 42, the direction of the spring thrust is such as to holdthe contactor in its closed position engaging the stationary contact.

The contactor, in conjunction with the pivoted lever or cam and thepitman assembly, thus eonstitutes a toggle structure to provide thedesired snap action and insure quick opening and closing of the switch.

the contactor arm and the end 3! of a switch actuating lever or cam 32pivoted on the stud Hi. The abutment is preferably an upstruck portionof the contactor arm [9.

The switch acuatin'g lever or cam 32 is formed of insulating material,and like the housing 5, is preferably molded of Bakelite or othersimilar material. As best shown in Figure 9, the lever or cam has a hubportion 33 apertured to receive the stud l4 and counterbored to receivethe head 34 of the stud. Y

As clearly shown in Figure 5, the head 34 is spaced from the innersurface of the bottom wall adjacent to the stud a distance sufficient toaccommodate the thickness of the contactor arms, the lever or camportion under the head, and a thin washer 35 interposed between thecontactor and the actuating lever or cam.

In the event the contactor, for some reason or the rocking of thesupported spring about the fulcrum provided by the projection or bOSs28.

The actuating lever or cam 32 in this position of the parts has not asyetreached the full limit of its'clockwise-rotation so that the posi-Projecting radially from the hub portion is the lever 3! against whichthe force of the toggle tured, as at 31, and the abutment 30 on theouter end of the contactor has an aperture 38. These apertures providefor the reception of a pitman 39 upon which the toggle spring ismounted.

In toggle switches heretofore in use, the spring generally has beenunsupported and as a'consequence, was very apt to buckle'and pop out" ofplace. This objection is entirely overcome with the presentconstruction.

The specific construction of the pitman is another feature of particularimportance from the standpoint of simplicity and low production cost. Itconsists merely of a U-shaped link having its closed end received in theaperture 31 and the outer ends of its two legs or reaches slidablyreceived in the aperture 38. While this U-shaped link may be formed ofany suitable wire or rod stock, it is preferable to use half roundcotter-key stock since it is cheap and readily obtainable in the openmarket.

Proper support for the end of the toggle spring which is adjacent to thelever 3| is provided by an H-shaped thrust plate 40 positioned betweenthe legs of the U-shaped link (see Figure 8) and between the end of thespring and the round edge of the lever 3|. An exceptionally inexpensiveand dependable construction is thus tively propelledclockwise motion ofthe lever or cam forcibly rocks the supported spring on its fulcrum.

The instant the contactor is freed in the manner above described, thekickoff is no longer effective and the contactor moves solely inresponse to the toggle spring. Figure 3 illustrates the parts in thepositions they occupy when the conmoves under the force of the togglespring be- Attention is directed to the-fact that although a desirablylong toggle spring is employed, the overall length of the pitman is heldto a minimum to insureicompactness. This is the direct result of thenovel pitman and spring arrangement andthe fact that the fulcrumabutments 21 and 28 engage the sides of the spring medial 1y of itsends.

Inasmuch as the pivotal connection between the contactor and the studcarries fcurrent, it

is important that this connection have a low electrical resistance.Ordinarily,' some special provision would be required to insure thiscondition; butwith the structure of this invention,

the toggle spring 29 at all times urges the contactor outwardly anddraws the edge of the opening therein against the stud with a force.sufficient to keep the resistance of the connection satisfactorily low.

As noted hereinbefore, the contactor is composed of the two superimposedarms I9 and 20, the former providing mechanical strengthand rigidity,while the latter serves as the main current carrying member.

To enable the knife action with which engage-j.

ment is effected between the contactor and the stationary contact, thelow resilient contact arm is oifset, as at 43. This construction hasbeen found exceptionally effective; but it is desired to point out thatthe contactor might be formed of merely the single arm I9 for the reasonthat the toggle spring exerts a downward thrust on the contactor whichnormally depresses the contactor arm l9 below the plane of the top.surface of the stationary contact and could be used for contactpressure.

In such a construction, however, it would be 55 occupies the positionindicated in dotted lines at 59 and the arms 36 of the actuating leveror cam are substantially equi-spaced therefrom, as shown in dottedlines. In this position of the parts, the contactor of the rheostat isat the position of maximum resistance so that as the operating shaftismoved in a direction to cut out necessary to space the actuating leveror cam its flat compact construction isobviously susceptible to a widevariety of uses, it is especially adapted for mounting on the back of arheo-- stat or volume control of the type employed in radio receivers.Adaptation of this use is illustrated in Figure 10. .As here shown, themetal cover 9 is substantially cup-shaped and provides the back of ahousing 45. It is secured thereto ln'any suitable manner preventingrelative rotation, as by a plurality of ears 46 projected from the edgeof the cup-shaped cover and connected with the side wall of theresistance housing 45.

The variable resistance mechanism, indicated generally by the numeral 41enclosed within the housing 45, forms no part of this invention and maybe of any suitable design or construction. For the purposes of thisinvention, it is sufiicient to note that the variable resistancemechanism,

in Figure 13, is a stamping having a flat body portion 52 bifurcated atone end to provide inwardly curved arms 53 with a tongue 54 extendingcentrally therebetween.

The outer opposite end of the body has a laterally projected lug 55extended therefrom which engages one or the other of the arms 36 on thelever or cam 32 during opening and closing of the switch.

The arm 5| is nonrotatably secured to the shaft end by having its tongue54 extend into a hole or slot 56 diametrically therethrough and byhaving its arms 53 received in and embracing an annular groove 51 inline with the hole or slot, as clearly shown in Figure 14.

The manner in which the shaft carried arm actuates the switch isdiagrammatically illustrated in Figure 11. As here shown, the lug on theouter end of the" shaft carried arm travels in a circular path,indicated by the arc 58 which intersects one or the other of the twoarms 36 on the lever or cam 32.

When the switch is in its off position, the lug the resistance, it firstcarries the driving lug 55 to the left, as viewed in Figure 11. Duringthis motion, the left arm 36 is engaged and the lever or cam 32 is swungto its full line position.

After swinging the lever or cam to its full line position which effectsclosure of the switch, further clockwise rotation of the operating shaftefiects only the adjustment of the rheostat. The driving connectionbetween the rheostat and switch is thus transient in character. To turnthe switch off, a reverse rotation is imparted to the shaft whichcarries the driving lug into the space between the arms 36 to swing thelever or cam to its dotted line position.

It is to be observed that the space between the arms 36 is sufliclent toprovide the necessary lost motion in the transient driving connection toinsure the switch being what is known as trip free." In other words, thespeed with which the switch moves from one position to the other is notdependent upon the rate of manual adjustment of the operating shaft,

While the switch actuating lever or cam is carried by the switchassembly and the actuating arm is carried by the rheostat assembly,proper cooperative engagement thereof is assured by virtue of the factthat the lever or cam 32 projects through the hole II in the cover andis thus brought into alignment with the driving lug 55.

The switch housing may be mounted directly 'on the cover 9 in whichinstance the housing must be deep enough to space all parts of theswitch mechanism from the plane of its open side to prevent contact withthe metal cover. However, insulating gasket members 60 and 6! may beinterposed between the cover and switch housing to obviate increasingthe depth of the housing. These gaskets have an external configurationsubstantially corresponding to the outline of the switch housing.

The gasket 6| which is considerably thicker than the gasket 60 is cutout to correspond to the outline of the cavity in the housing so that itforms in effect an extension of the housing side wall, while the gasket60 overlies the inner surface of the metal cover wall to preclude thelive switch parts contacting the metal wall; and.like the metal coverwall, it has a hole 62 of substantially the configuration of the hole llpositioned to align therewith.

The hole 62, like the hole II in the cover, accommodates the movement ofthe switch actuating lever or cam and being slightly smaller than thehole I l, guards against the possibility of having the lever or camstrike the raw metal edge of the hole H.

Assurance of proper alignment or registry between the hole in the coverand the hole 62 in the gasket 60, as well as proper location of thegaskets with respect to the switch housing and the metal cover, isobtained by having the fasten- .ing means l0 pass through aligned holesin the metal cover, the gaskets and the lugs 8.

From the foregoing description takenin connection with the accompanyingdrawings, it will be readily apparent to those skilled in the art thatthis invention provides an exceptionally compact switch which, by virtueof the fact that all moving parts thereof travel in parallel planes,permits the entire mechanism to be assembled within a relatively shallowhousing. This is desirable from the standpoint of keeping the overalldimensions of a combination volume control and switch down to a minimum.

What I claim as my invention is:

1. In a snap switch, the combination of: a housing; a stationary contactsecured in the housing; a movable contactor pivoted in the housing forengagement with the stationary contact; projections on the side walls ofthe housing engageable with the contactor for defining its limits ofmotion; an actuating member pivoted in the housing; and spring operatingmeans connected between the actuating member and the contactor includinga coil spring supported on a pitman, said supported spring beingengageable medially of its ends with said projections and rockablethereon by the actuating member to force the contactor positively awayfrom its limits of motion. a

2. In a snap switch: a movable contactor memher; an actuating member; alink connecting said members; a thrust plate carried by said linkcomprising a pair of parallel lateral portions spaced apart by atransverse portion; and a spring bearing against said lateral portions,said actuating member bearing against said transverse portion to opposethe force of the spring.

3. In a snap switch: a movable contactor comprising a pivoted rigidcarriermember, said carrier member having a contact portion at its outerend provided with a flaredlateral edge; a coaxially pivoted resilientmember secured to said carrier member and having a contact portionopposite that of the carrier member and provided with afiared lateraledge spaced inwardly from the flared edge of the contact portion on thecarrier member; and a stationary contact engageable between said contactportions.

4. In a snap switch, the combination of a recessed housing member;switch mechanism in the recess of the housing member including contactormeans movable between defined limits; an actuator; means mounting theactuator in the recessed housing member for movement between definedlimits; a spring connecting the actuator with the movable contactormeans, said spring acting to snap the movable contactor means from oneposition to the other as the actuator is moved from one to the other ofits limits of motion; and I spaced abutments defining the limits ofmovement of the contactor and engageable by the side of said springmedially of its ends to increase the force appliedtothe movablecontactor means and insure response of the contactor means to operationor the actuator.

5. In a snap switch, the combination of: a base of insulating material;a stationary contact mounted on the .base: a pivot post mounted on thebase and spaced from said stationary contact; a contactor pivoted onsaid. post to swing'across the base to and from'engagement with thestationary contact; an actuator pivoted on said post; means for definingthe limits of pivotal motion of the actuator; a toggle spring connectingthe actuator and contactor and operable to snap the contactor from oneposition to the other as the actuator is moved across dead center; andspaced abutments on the base in the path of the contactor and the springmedially of its ends so that said abutments define limits between whichthe contactor may swing and provide fulcrums engageable by the springmedially of its endsand about which the spring rocks to impartadditional force to the contactor and thus initiate motion of thecontactor in the event said contactor fails to respond.

6. In a snap switch of the character described: a switch base ofinsulating material; a stationary contact mounted on the base with aprojecting portion thereof spaced from the base; a fixed pivot mountedon the body at a distance from said stationary contact with its axisnormal to the plane of the base; a contactor mounted to swing about saidpivot toward and from said stationary contact, said contactor havingsuperimposed contact portions adapted to engage under and over saidprojecting portion of the stationary contact, the contact portion whichengages over the stationary contact extending beyond the other contactportion to engage the stationary contact first and leave the stationarycontact last during closing and opening of the switch, respectively;means for snapping the contactor from one position to the otherincluding a spring so connected with the contactor as to impart adownward thrust thereon to normally yieldingly maintain the uppercontact portion of the contactor slightly below the plane of saidprojecting portion of the stationary contact: and means for guiding theupper contact portion onto and over the pro- :le'cting portion of thestationary contact. I

7. In a snap switch: a movable contactor having two superimposed contactportions, both of which have outwardly flared lateral edge portions, oneof saidcontact portions being resilient and the other rigid, the rigidcontact portion having its flared edge portion extending beyond theother to provide an arcing horn; a pivot mounting the contactor so thatits contact portions with their flared edge portions are movable in anarc and a stationary contact mounted on said arc to be engageablebetween the contact portions of the movable contactor.

NEWTON C. SCHELLENGER.

